As will be appreciated by those familiar with printer technology, a conventional ink-jet printer includes a printhead which deposits ink onto media such as paper sheets. The printhead is mounted on a bi-directionally movable carriage, such carriage being configured to reciprocate back and forth across the paper as printing occurs. The structure and operation of such printheads and carriages are well known to those skilled in the art.
In order to keep printheads in proper working condition, most ink-jet printers employ mechanism at some point along the printhead's path to periodically service the printhead during normal use. Such mechanism generally includes a wiper with a wiping edge which sweeps across the printhead to clear its printing surface of contaminants such as dried or drying ink. In the past, wipers have been molded from an elastomeric material such as ethylene polypropylene diener monomer (EPDM), a material chosen for its flexibility and conformality to the printing surface of the printhead.
Conventional wipers, it will be noted, include a chassis-mounted base and an elongate blade which extends from the base to a tip which engages the printhead's printing surface when the printhead passes thereacross. The blade is typically planar and is of a size determined by the physical characteristics of the printer in which it is employed. In known ink-jet printers, the length is approximately 0.300-inches (accommodating printhead interference) and the width is approximately 0.315-inches (ensuring that the wiper will wipe the entire printhead). The blade's thickness is determined with these parameters in mind to produce a wiper which exerts a desired force on the printhead upon interference engagement therewith. Conventional EPDM wipers have blade thickness of approximately 0.050-inches.
Although conventional wipers have proven effective when new, the just-described arrangement presents particular problems as the wipers wear. After continued use, the wiping edges become rounded due to the repeated passage of the printhead thereacross. As the edges wear, the effectiveness of the wiper declines due to the increase in the surface area which contacts the printing surface of the printer's printhead. This increased surface area results in a hydroplane effect, the wiper passing over contaminants without wiping them away.
One possible solution to this problem would be to increase the force exerted by the wiper on the printhead, this diminishing the tendency of the wiper to hydroplane. This solution, however, would lead to increased wear of both the wiper and the printhead, an unacceptable result. It would therefore be desirable to form a wiper which avoids the effects of wear, but which operates with a relatively low force on the printhead.
Another problem with conventional wipers is related to the cost of manufacture, such wipers generally being molded to within precise tolerances so as to produce a wiper of the desired size and flexure characteristics. It is an object of this invention to provide a wiper which is more readily manufactured than conventional molded wipers.